Improvement in safety-brakes on elevator-platforms



H. SNOWDEN. SAFETY-BRAKE on ELEVATOR-PLATFORMS.

No.17Z,79Z. Patented Jan. 25,1876.

ILPETERS. 'YNOTO-UTNOGRAFNER. WASHINGTON. D. .c.

UNIT D STATES PATENT QFFICE.

HENRY SN OWDEN, OF BALTIMORE, MARYLAND. I

IMPROVEMENT IN SAFETY-BRAKES ON ELEVATOR-PLATFORMS.

Specification forming part of Letters Patent No. 172,792, dated January 25, 1876; application filed I December 1, 1875.

To all whom it may concern:

Be it known that I, HENRY SNOW'DEN, of the city of Baltimore, State of Maryland, have invented certain Improvements in Safety-Brakes on Elevator-Platforms, of which the following is a specification:

The first part of my invention relates to certain racks and links and clamping-bar placed on and, attached to the platform itself of the elevator, in such manner that, being firmly stayed across the guide, they clamp the latter automatically on the occurrence of any sudden fall of the said platform from its fastenings.

Figure 1 is a vertical and lateral section of my brake, its racks, links, clamping-bar, and

stays in position, embodying my invention.

Fig. 2 is a detail view, showing the lever f, Fig. 1. Fig. 3 is a rear elevation'of the upper part of my brake, showing the fulcrum of lever, cross-beam for attaching the hoistingrope, holding the upper end of guides of the elevator, 8m.

a is one of the guides supporting and conducting the platform.

b, Figs. 1 and 3, are clamping-bars.

c, 'Fig. 1, is a stationary rack, connected, by stays at d, Fig. 1, to clamping-bar b, and

firmly securedto the cross-head k, Figs. 1 and 3, and to the platform-floor.

d d are stays, Figs. 1 and 3, holding in place rack c and clam ping-bar b.

e e e is a movable rack, having a slight vertical motion controlled by lever f, Figs. 1 and 2.

f is a lever, operated by the rope g g, Fig. 1.

h h are stationary carrier-pulleys,which receive the rope g g, and admit of the latter running in accordance with the movement of the platform.

t t" t i are links, auxiliary in clamping movable rack'e e c, Fig. 1, and clamping-bar 1), Figs. 1 and 2, against the guides a.

It is the cross-head of the platform arrange ment, to which the hoisting-rope n, Figs. 1 and 3, is attached.

1, Figs. 1 and. 3, is a cross-bar, holding together the movable racks e, which are on 01)- posite sides of the platform, and also having a slotted suspender to support and work lever f, Figs. land 2.

a m is the hoisting-pulley, Figs. 1 and 2.

n is thehoisting-rope, Figs. land 2. p

o' is a spring in form of a double cone, connected at the lesser diameter, and opened along its length to admit the rope g.

10 is a friction-nut, to press on carrier-pulley h, Fig. 1.

A is the top of the elevator. B is the bottom of the elevatorthe floor. The operation of my improved elevator safety-brake is thus: As the platform is raised, carrying up every part of my brake, the fulcrum of lever f assumes a position that permits the said lever (its long arm being attached to rope g) to free the movable rack e from the clamping-pressure at the inclines, and enables an unrestricted upward motion.

When the platform falls from casualty the reverse of the above-named movement happens.

A sudden fall causes sufficient friction on the carrier-pulley h, Fig. l, to operate (raise) the lever f, and with it the movable rack 9, until the inclines of the latter engage the inclines of stationary rack 0, when, with the assistance of links 't' 12 t i, the clampingibar on the one side and the said movable rack on the other side of the guide of the elevator, clamp the said guide firmly, and thus sustain and support the platform, not by a heavy blow, but by powerful and steady pressure.

Having thus described my invention, what of an elevator -guide, connecting a movable and a stationary clamping-piece, for the purpose of clamping between the said pieces the guide or guides of the elevator, for the purposes specified.

3. Iclaim the combination of a movable rack, Q

a stationary rack, links 11, lever f, and clamping-bar with an elevator-platform, to make a I A safety-brake.

' HENRY SNOWDEN.

Witnesses:

. OLARENGE GREENE, JAMES HART.

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